Current wireless systems are based on embedding information in variations from a source (transmitter) to be sent, using an antenna, through a static or slowly varying wireless channel to a destination (receiver). It is also desirable to have high spectral efficiency, and low probability of error (outage). Wireless systems suffer from fading caused by multipath Radio Frequency (RF) wave propagation. Diversity can be used to combat the effect of multi-path fading.
Multiple-Input Multiple-Output (MIMO) antenna systems are used as a way in which to realize diversity or increase spectral efficiency in wireless systems. In particular, spectral efficiency of a M×N MIMO system scales with the multiplexing gain which is min(M, N), (i.e., smaller of M and N). In addition, to reduce the effect of multipath fading, a system can be configured to tradeoff multiplexing gain against diversity order.
Thus, there are advantages in having a wireless system that offers the benefits of MIMO systems in terms of spectral efficiency and diversity with a smaller number of antennas.
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The apparatus and method components have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments of the present invention so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein.